Optimum driving modes, electric, ICE and recharge

Apologies sure this will have been asked before, but I can't find it.
I know the phev is more efficient running at low speeds using electric (0-30mph) and higher speeds (50-60mph +) using ICE. But what conditions should I use ice to charge, assuming the journey is more than the battery range.

I guess another way of putting it is, what is the point of charge mode, why not just use save.

Ddalley said:

Apologies sure this will have been asked before, but I can't find it.
I know the phev is more efficient running at low speeds using electric (0-30mph) and higher speeds (50-60mph +) using ICE. But what conditions should I use ice to charge, assuming the journey is more than the battery range.

I guess another way of putting it is, what is the point of charge mode, why not just use save.

Click to expand...

That is what I do - use "Save". Others here who are seeking maximum fuel efficiency will tell you that that is best achieved by letting the battery run relatively low at which point the ICE is better able to optimise fuel consumption because the battery will accept a higher charge current. If you do that and then want an increased charge level either to climb some steep hills or because you are environmentally responsible and want to run on EV through populated areas, then you may want to use "Charge" to bring the battery level back up again.

Trex, who is a regular here, has run tests and claims that there is a difference of something like 8% in fuel economy between running on petrol in Save mode with a full battery and running on petrol with a flat battery. He does live in Australia and was able to run his tests at a steady cruising speed over many miles on flat roads. I tried a similar test on motorways in the South East of England and could not detect any difference - YMMV!

Ddalley said:

Apologies sure this will have been asked before, but I can't find it.
I know the phev is more efficient running at low speeds using electric (0-30mph) and higher speeds (50-60mph +) using ICE. But what conditions should I use ice to charge, assuming the journey is more than the battery range.

I guess another way of putting it is, what is the point of charge mode, why not just use save.

Click to expand...

It depends on your expectation for the rest of the journey "Save" tells the car: "this is all I need when we leave (f.i.) the motorway" , "Charge" means " We will need all you can generate for later" (for instance to climb a hill, or entering an emission controlled zone)

I have made some tests, and this is what works the best for me.
I usually do not use the car for very long trips, usually i can manage with just electric, but if i know i will drain my battery this is what makes my consumption the lowest.
I Always start with full battery, all roads below 70km/h i use battery, when the car speed is above 70km/h and the battery is max 50% i press "save", the ICE starts and run for app. 30 sek, then it connects to the wheels, the orange Arrow and the RPM of the ICE drops. then i run with the "save" butten pressed unit i have to turn or smimilar when the speed drops, i unpress save well in time to use the B0 to be as efficient as possible, then i turn and accelerate smoot up to abowe 70km/h on electric and then i press save again.
And Always calculate so you arrive with empty battery, only heat the cabin when the ICE is running.
With this driving cycle i use to drive app 60km with a consumption below 0.2

To use the ICE below 70km/h, i have noticed the RPM of the ICE is very high to generate the needed power, i think it is a very un efficient way of making the needed Power, therefore i only try to use the ICE when it will be connected to the wheels, and keep the RPM down.

Works for me.

The last is not correct. The motor management is geared to maximum efficiency vs power demand. It is probably at its most efficient at 4500 RPM at full power, Anko has nice graphs.
The car will switch to the most efficient mode automatically.

I tend to agree, although I think the engine is not running anywhere close to max RPM. We are so used to not hearing the engine that we are easily led to believe it is really in a hurry. Plus, the relation between vehicle speed and engine RPM 'does not add up' adding to the believe the engine is racing. I can imagine people that are used to CVT's will have a somewhat different experience.

BTW: in serial mode the engine will not run faster than 4100 RPM anyway, even when tasked to to max. It doesn't need to as the power output would exceed the specs of the generator. The last 400 RPM are reserved for the German Autobahn :mrgreen:

But, do not forget, the engine is propelling the car AND recharging the battery. And in serial mode I think it will do so much faster than in parallel mode and in order to do so, it must put out much more power than needed for just driving.

A petrol engine is not most efficient at highest RPM, it is most efficient where you have the highest torque. It is high up in the RPM for a petrol car, but not at the top, and lower for diesels.
Therefore I will burn less fuel/km, as you see I am NOT talking about effciency, I am talking about range, and this is what i am concerned about, not if my ICE run at 26 or 28% efficency, when the ICE runs at lower RPM with higher torque, as it does when it also powers the wheeles
Therefore with my measures, you can argue if you want, I reach longer per liter of fuel if I run the ICE when it has the possibillity to also power direct to the wheels by pressing the save button and to use the electricity in slower traffic+ accelerations on to highway and similar.

MartinH said:

A petrol engine is not most efficient at highest RPM, it is most efficient where you have the highest torque. It is high up in the RPM for a petrol car, but not at the top, and lower for diesels.

Click to expand...

Guess again .... It is the red line .....

MartinH said:

..., I reach longer per liter of fuel if I run the ICE when it has the possibillity to also power direct to the wheels by pressing the save button and to use the electricity in slower traffic+ accelerations on to highway and similar.

Click to expand...

I totally agree. But mostly because you eliminate two energy conversion steps (generator and E-motors) by using parallel drive as much as possible (as long as you do not arrive at your destination before draining your battery).

What does this graph shown, drive resistance?, but this has nothing to do with Engine RPM. This can not be when the engine is also connected with the wheels if the lower numbers are km/h.

If the car is in parallel mode the engine RPM is in a 1:1 relation to the car speed.

If so, i dont delieve the graph, sorry!
I think you will get the Nobel price! if you can get a 2.0 liter petrol engine, without turbo, to deliver 140 Nm at 1500 RPM, what will be the case at 40km/h, or even lower.
Or am i stupid and not get it correct?

The ICE cannot go into parallel mode @ 40 kph.

I know, but that is what you said te graph shows, thats why i did not believe the graph.

So, what does the graph then shows?

Normally, for a car equipped with gears, you would show 'power available (in optimal gear) versus power needed for driving' in order to get an idea of the cars power reserves. In case of our parallel drive, there is only one gear available, so they decided to show 'torque available from the ICE versus torque needed for driving' in order to get an idea of torque still available for charging.

Indeed, for speeds below 65 km/h this graph is pure theoretic, hence the first dotted line. And at speeds above approx. 120 km/h no substantial charging takes place, hence the second dotted line.

To get an idea of engine performance, you could change the X-axis from km/h to RPM, by dividing the values by 170 and multiply by 4500. This would result in 0 RPM at the far left side of the graph and 4500 at the far right side of the graph and produce a more standard torque graph.

I do not think the graph is correct, with your statement abowe, i get the 1:1 ratio to 70km/h will result in a RPM of app 1850.
The graph shows app 160Nm at this RPM, and this is not possible for our Engine, or have i missed something i develompent of new gas engines. :lol:

Maybe you have. I am definitively not an expert on that subject, so I do not know.

Either way, the reason for bringing in the graph was not to discuss "torque at low RPM" but to shed light on your statement about optimum RPM from an efficiency perspective.

Yes, we still discussing the efficiency, or actually not the efficiency, but to extend the km per liter of fuel, this has not to do with only efficiency, there is alot of other factors involved. Therefore my statement is still that you should avoid using the ICE when it has not the possibility to Parallell Power, to keep the RPM down, and the torque up. to extend the km per liter of fuel.
About the graph, i have to analyse everything i see, many just thinks if you have made a fancy graph, it must be correct, this is not always the case. In this graph the torque is 160Nm starting below 2000rpm and have almost a flat curve, for a 2.0 liter non turbo Engine, I do still not think it is correct.

MartinH said:

Yes, we still discussing the efficiency, or actually not the efficiency, but to extend the km per liter of fuel, this has not to do with only efficiency, there is alot of other factors involved.

Click to expand...

Such as? Keep in mind, we were talking about driving modes and recharge policies, not driving styles ;-)

MartinH said:

you should avoid using the ICE when it has not the possibility to Parallell Power, to keep the RPM down, and the torque up. to extend the km per liter of fuel.

Click to expand...

To this we have already agreed. Although I think it is mainly to prevent energy from being converted twice.

MartinH said:

About the graph, i have to analyse everything i see, many just thinks if you have made a fancy graph, it must be correct, this is not always the case.

Click to expand...

You are aware that this is official Mitsubishi material? Not that that defines it as being correct, but it is not something I created myself.

It is important to work activley with the save button to have the ICE to run att the correct times, If you know you are going to turn 500 meters ahead, turn of the ICE and use very Little Power from the battery, and use up to B5 before the turn, after the turn accelerate with the ICE not running, and press the save when 70km/h, continue to accelerate. Shut the ICE of before you go downhill, use the energy to roll as far as possible, then press save again, I do not know if it is efficient, but you will reach longer per liter of fuel.
And again, because the graph is a offical grapf, you have to believe it? it cleraly states Parallell + charge, and it shows torque down to 40Km/h. we all know that parallell down to 40km/h is not possible, but why is it then show in the graph?

MartinH said:

And again, because the graph is a offical grapf, you have to believe it?

Click to expand...

So we should believe you instead? ;-)

MartinH said:

it cleraly states Parallell + charge, and it shows torque down to 40Km/h. we all know that parallell down to 40km/h is not possible, but why is it then show in the graph?

Click to expand...

I did make an effort to explain the meaning of the first dotted line and you choose to ignore that. Can't be helped.